powerpc/85xx: fix timebase sync issue when CONFIG_HOTPLUG_CPU=n

Browse source

When CONFIG_SMP=y, timebase synchronization is required when the second
kernel is started.

arch/powerpc/kernel/smp.c:
  int __cpu_up(unsigned int cpu, struct task_struct *tidle)
  {
  	...
  	if (smp_ops->give_timebase)
  		smp_ops->give_timebase();
  	...
  }

  void start_secondary(void *unused)
  {
  	...
  	if (smp_ops->take_timebase)
  		smp_ops->take_timebase();
  	...
  }

When CONFIG_HOTPLUG_CPU=n and CONFIG_KEXEC_CORE=n,
 smp_85xx_ops.give_timebase is NULL,
 smp_85xx_ops.take_timebase is NULL,
As a result, the timebase is not synchronized.

Timebase  synchronization does not depend on CONFIG_HOTPLUG_CPU.

Fixes: 56f1ba2807 ("powerpc/mpc85xx: refactor the PM operations")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210929033646.39630-3-nixiaoming@huawei.com

...

This commit is contained in:

Xiaoming Ni 2021-09-29 11:36:46 +08:00 • committed by Michael Ellerman

parent 3c2172c1c4

commit c45361abb9

3 changed files with 13 additions and 7 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

4

arch/powerpc/platforms/85xx/Makefile

View file

4

arch/powerpc/platforms/85xx/mpc85xx_pm_ops.c

View file

12

arch/powerpc/platforms/85xx/smp.c

View file